PSUs with Active or overridable semi-passive fans

[MonkeH]

Just curious to know which of the currently available platforms still offer active or manual override or non-semi (0 rpm) passive fan operation?

The ones I'm aware of so far:

Superflower - Leadex I/II/III - "eco" semi passive mode with override
Seasonic prime/focus/core etc - either S2FF active or Hybrid with override
Bitfenix formula/whisper/bpa - active with variable speed
be quiet! dark pro/straight- active with variable speed
Fractal ION - 0db - semi passive mode with override
Asus ROG Thor - (same as Seasonic Prime)
Corsair RMi/HXi - possible if custom fan curve is specified via software.
Corsair TX-M/CX - active with variable speed.

[Jon Gerow]

Corsair TX-M/CX - active with variable speed.

Almost any quality PSU is going to have a thermostatically controlled fan. This is not uncommon.

[MonkeH]

It seems that many of the premium units are now using some form of semi-passive cooling. I guess this is as a result of noise and efficiency targets.

I can only imagine this creates some design challenges.
I know from my experience in electrical repair I often found thermal cycling to be a problem (trailing user error/abuse and mechanical failure - e.g. vibration, servo, contactor, fan etc).

[Jon Gerow]

It seems that many of the premium units are now using some form of semi-passive cooling. I guess this is as a result of noise and efficiency targets.

I can only imagine this creates some design challenges.
I know from my experience in electrical repair I often found thermal cycling to be a problem (trailing user error/abuse and mechanical failure - e.g. vibration, servo, contactor, fan etc).

Well, let's just say some controllers are smarter than others.

Corsair, for example, doesn't only rely on internal temperatures, but also load. This data is given to an MCU that has a programmed algorithm that takes these two parameters into account, as well as how long the fan should spin so the temperatures drop below a particular threshold to prevent the fan from spinning up again after only a short period of time.

Unfortuantely, most fan controllers, including those that implement a zero RPM mode, only measure temperature and control the fan with a varistor. The zero RPM may just be controlled by an analog IC that doesn't feed power to the varistor unti a certain temperature is reached, but load and duration are not a consideration.

[ehume]

I have an Antec that was reviewed here in 2009. It has an always-on fan. You cannot hear it at idle. The rest of my PSUs have an on-again-off-again fan system that interfered with my heatsink reviewing until I got a fanless PSU for my review systems. Thus I have experienced all three kinds of systems. Given my druthers, I'd rather have the always-on system. I don't pretend it's not just personal preference, though I've seen arguments both ways.

[ashiekh]

I am for always on (but temperature responsive) as kicking in can be more annoying than humming along quietly.

[Mezoxin]

I am for always on as well , I set a custom fan profile for my rmi850 , sadly the minimum startup rpm for the fan is 40% (700rpm) , its almost silent though at that speed

[MonkeH]

I think always on is a nice option to have, especially with most cases these days having a PSU shroud and inverting the PSU.
It is a shame the RMX doesn't have an button to toggle an always on fan starting @ minimum, Perhaps it could go on the wish list for v3